SanDisk Extreme SSD 240GB vs OCZ Vertex 4 256GB SSD

So a SandForce and an Indilinx controller walk into a testbed…

Are SSDs approaching commodity status? There are dozens of different consumer SSDs on the market, but with each successive generation it seems there are fewer controllers driving them. This time around the big players are LSI’s SandForce SF-2281 controller (found in OCZ’s Vertex 3 and Agility 3 drives, Patriot’s Pyro SE, Corsair’s Force 3 and Force GT, OWC’s Mercury Extreme Pro, Intel’s 520 Series, and so many more) and Marvell’s 9174, found in pretty much everything else. Samsung’s 830 Series drives have their own controller, but most of the rest of the market has one of two controllers, differentiated only by firmware and NAND choice. Here we examine two new SSDs: one with an off-the-shelf controller and one with a heavily modified one.

SSD vendors that make one or more components of their drives tend to do better than those who just slap commodity parts on a board and call it a day. Sounds reasonable, right? SanDisk’s Extreme SSD is yet another drive based on the LSI SandForce SF-2281 controller, a 6Gb/s SATA SSD controller with speedy sequential reads and an emphasis on hyper-fast queued random writes.

However, because it is a NAND manufacturer, SanDisk has the means to use its own 24nm toggle-mode NAND—eight 256Gb packages in the 240GB version—instead of commodity NAND. Like other SF-2281-powered drives, the Extreme SSD uses the extra 16GB of NAND for overprovisioning and write caching.

SanDisk’s Extreme is a plain black metal box with a sticker on it and speed inside.

Contrary to its name, the Extreme SSD isn’t very extreme—at least not in the sense of being unusual. It’s a good implementation of the SF-2281 controller combined with high-quality NAND, so it’s not exactly rare, but that still means it’s one of the fastest consumer drives on the planet. With sustained read speeds over 480MB/s and writes around 280MB/s, its performance is what you’d expect from a good SandForce drive—faster than the Intel 520 in reads, slower in writes. Its random performance is classic SandForce territory too—heavily optimized for high-queue-depth 4KB random writes, with over 90,000 IOPS at a queue depth of 32.

There aren’t any surprises with the SanDisk Extreme SSD, but that’s not a bad thing. It’s fast, inexpensive (just over $1/GB at this writing), and based on a proven platform. You really can’t go wrong.

OCZ has typically reserved its Vertex label for the highest-performing SSDs in a given generation—using synchronous NAND, for example, rather than the asynchronous NAND found in its less expensive Agility series. The 256GB Vertex 4 carries on that tradition, with 16 128Gb IMFT 25nm synchronous NAND packages on a board with 512MB of DDR3 DRAM cache and OCZ’s new Indilinx Everest 2 controller.

It was just a few months ago that OCZ shipped its Octane SSD, which was powered by the first Indilinx Everest controller. Some digging by Anand Lal Shimpi of AnandTech.com revealed that the Everest controller was actually based on Marvell’s 9174 controller—the same one used in drives by Plextor, Intel, Crucial, and more, but with custom Indilinx-engineered firmware that allowed the Octane to outperform earlier Marvell-based drives. The Everest 2 controller, while also based on a Marvell one, is aimed even higher.

The Everest 2 controller in the Vertex 4 is a modified Marvell controller with custom Indilinx firmware.

The Vertex 4’s sequential reads, at 440MB/s in CrystalDiskMark and 460MB/s in AS SSD, are impressive, though Samsung’s 830 and any number of SandForce-based drives hover closer to 500MB/s. Where the Vertex 4 really stands out, though, is in its write speeds: We saw sustained writes of over 450MB/s, which is absurd—50 percent faster than a SandForce-based SSD. We also saw great results in 4KB read and write performance, both single-queued and heavily threaded. Though not included in our benchmark chart, the Vertex 4’s 64-thread 4KB random read and write IOPS (as measured in AS SSD) are over 20,000 IOPS higher than the next-fastest SSDs. Strangely, our Iometer 32QD 4KB random write test didn’t show such a strong performance lead. In fact, at 65,000 IOPS, the Vertex 4 was about a third slower than an SF-2281-based drive. Our Iometer test also highlights a potential weakness in the Everest 2 controller: Its maximum response time during our test was a whopping 285ms. That’s about eight times the lag we’d see from a SandForce-powered drive, though only about half the 429ms maximum response time on OCZ’s Octane drive. Other SSDs based on Marvell controller architecture also have maximum lag times in the 100ms to 500ms range.

Its blazing-fast write performance meant that the Vertex 4 edged out all comers in our Premiere Pro test, albeit by just a few seconds. In PCMark Vantage and 7’s storage suites, the Vertex 4 doesn’t do quite as well as a SandForce drive, but the differences are minimal.

With an MSRP of $350, the 256GB Vertex 4 isn’t as inexpensive as a 240GB SandForce-based SSD, but it’s already under $300 on the street, which is pushing close to the magical dollar-per-gigabyte price point. Frankly we can’t believe how far SSDs have come in the past year alone.

The Vertex 4’s write speeds are truly astounding, and the read speeds are nothing to scoff at, either. We’re happy to see OCZ forging its own path with the Everest 2 controller. Even if it’s not, strictly speaking, new silicon, the magic firmware sauce is working here.